Pneumatic control apparatus



Feb. 15, 1966 w, PIERCE, JR 3,234,739

PNEUMATIC CONTROL APPARATUS Original Filed April 2?, 1960 INVENTOR Waqne M. mvce, Jr.

Rec/0am. MA D8560 ATTORNEYS United States Patent 3,234,739 PNEUMATIC CONTROL APPARATUS Wayne M. Pierce, Jr., Milford, Comm, assignor to Hunt- Pierce Corporation, Milford, Comm, a corporation of Connecticut Original application Apr. 27, 1960, Ser. No. 24,955, now Patent No. 3,132,718, dated May 12, 1964. Divided and this application May 11, 1964, Ser. No. 366,383 Claims. (Cl. 6062.6)

This invention relates to pneumatic control apparatus and relates more particularly to control apparatus particularly useful on power-operated boom structures for lifting a workman aloft such as shown and described in my copending patent application, Serial No. 24,955, filed April 27, 1960, now Patent No. 3,132,718, of which the present application is a division.

Boom structures for lifting a workman aloft are often employed to service overhead lines carrying high voltages which present a hazard to workmen and others near workmen. It is desirable that workmen carried aloft have within easy reach controls for effecting the various movements of the booms. The employment of pneumatic controls for this purpose is highly advantageous in that the pneumatic transmission lines which extend throughout the length of the booms may be constructed entirely of dielectric material, thereby reducing shock hazard. It should be understood, however, that my invention is not restricted to pneumatic control apparatus for controlling the movements of boom structures.

One object of the invention is to provide an improved pneumatic control apparatus.

Another object is to provide apparatus such as characterized above, having an open air system which is selfcharging and which permits air to enter and leave the air transmission lines.

Another object is to provide pneumatic apparatus which may be exposed to the elements, which has efiicient provisions for preventing water from entering the air system.

Yet another object is to provide apparatus such as characterized above, having a relatively simple construction, which apparatus is very efiicient and reliable in use.

In the drawing:

FIG. 1 is a diagrammatic view of pneumatic control apparatus embodying my invention;

FIG. 2 is an elevational view, partially broken away, illustrating the air transmitter of the control apparatus;

FIG. 3 is a sectional view of a slave unit or receiver operated by the mechanism of FIG. 2; and

FIG. 4 is a fragmentary view on a larger scale illustrating in vertical section certain parts of the transmitter shown in FIG. 2.

In the drawing the transmitter is indicated generally at 115. The transmitter may be supported on a suitable control panel 117. The slave unit or receiver is indicated at 116. It may have any suitable support, not shown. The transmitter and receiver are connected by a length of tubing 114 which, as previously indicated, may be constructed entirely of dielectric material.

The transmitting mechanism 115 (FIG. 2) has a cuplike lower part 118 having in the side wall structure thereof and near the bottom an inlet and outlet 119 and having in the center of the bottom an air outlet 120. A vertically arranged bellows 121 is disposed in the bottom portion of the cup part 118 and has an upper end fitting 122 in fixed relation to the bellows and a lower end fitting 123 also secured to the bellows. The fitting 122 closes the upper end of the bellows except in the central region thereof, and in this region the fitting 122 has an upward extending tubular part 124, providing an opening communicating with the interior of the bellows 120.

3,234,739 Patented Feb. 15, 1966 The upper extremity of the tubular part 124 is tapered, as at 125, and, as best shown in FIG. 4, this tapered portion is provided with a circumferential groove 126 seating a resilient O-ring gasket 127 forming a valve seat.

The lower fitting 123 closes the lower end of the bellows except in the central region thereof, and in this region is internally threaded to receive a nipple 128 on the air line 114, the nipple extending into the cup part 118 through the air outlet 120. The fitting 123 has in communication with the last-named threaded part a tubu lar part 129 extending upwardly in the bellows and opening into the latter.

As shown in FIG. 2, the lower end of the bellows is rather narrowly confined between the tubular part 129 and the cup part 118. The upper end of the part 118 is filled by an insert 130 secured to the side wall structure of the part 118 as by a screw 131. The insert 130, which has a central bore 132 therethrough enlarged at the lower end by a counterbore 133, has a peripheral shoulder 134 to abut the upper edge of the cup part 118. As shown in FIG. 4, the tubular part 124 of the upper bellows fitting may be extended with clearance into the counterbore 133.

Above the cup part 118, the insert 130 has a reduced externally threaded portion 135 threaded upwardly through the panel 117 for support by the latter, and the upper end of the portion 135 receives a nut 136 over a washer which bears against the top of the panel 117. A plunger 138 which extends loosely into the portion 132 so that air may pass lengthwise along the plunger, has an enlargement 139 in the lower end thereof to abut the bottom of the counterbore 133 and thereby prevent separation of the plunger from the insert 130 on upward movement of the plunger. As shown in FIG. 2, the enlargement 139 of the plunger is considerably smaller in diameter than the side wall of the counterbore 133. The plunger 138 normally extends a distance above the insert 130, and at the upper end thereof is provided with a disk 140 secured thereto and providing a button to move the plunger downwardly upon hand pressure of an operator thereagainst. A flexible cover 141 of the well-known accordion type embraces the plunger 138. The cover has one end thereof suitably fixed at the upper part of the plunger below the disk 140 and has the other end disposed over the nut 136.

The enlargement 139 of the plunger has a conical recess 143 in the bottom thereof approximating the taper of the portion 125 of the tubular part 124, the last-named recessed part forming a valve for seating engagement with the valve seat 127. The upper end fitting 122 of the bellows 121 normally occupies the position shown in FIG. 4. Within the cover 141 a compression spring 141 is provided acting between the nut 136 and the disk 140 and embracing the plunger 133. The last-named spring, which may be omitted if the cover 141 is sufiiciently resilient, normally maintains the plunger 138 in the position of FIG. 4. In this position the plunger is spaced upwardly from the upper end fitting of the bellows 121 to permit air to enter or escape from this bellows and the air line 114. When the button 140 is depressed through hand pressure, the plunger 138 seats on the upper end fitting of the bellows, cutting off the entry of air to the bellows, and compresses the bellows to transmit, through the line 114, air under pressure of the air-receiving mechanism 116, such as that shown in FIG. 3.

The air line 114 has a nipple 145 connecting the line to a fixed end (FIG. 3) of a bellows 146, forming a part of the air-receiving mechanism or slave unit 116, the lastnamed end being fixed by a bracket 147. The nipple communicates with the interior of the bellows 146, and the other or movable end of the bellows 146 is closed bya fitting 148 including a plunger 149 extensible into the switch 150 to engage and move a spring-biased leaf member 151. The leaf member 151 has a contact 152 and is biased in a direction toward a fixed contact 153 to normally engage the latter with the contact 152. The leaf member 151, which is a conductor and has a terminal 151*, is provided with a contact 154 for cooperation with a fixed contact 155. When the bellows 146 is extended by air pressure from the air line 114, the plunger 149 is extended to engage and move the leaf member 151 in a direction to break the electrical connection between the contact 153 and the terminal 151 and establish an electrical connection between the contact 155 and the terminal 151 through the contact 154. It will be understood from the foregoing that when the button 140 is released by the operator, the bellows 121 is permitted to re-expand through movement of the spring-biased plunger 138 upwardly. This results in contraction of the bellows 146 which retracts the plunger 149, allowing the biased leaf member 151 to disengage the contact 155 and reestablish the electrical connection between the contact 153 and the terminal 151 through the contact 152. It may be noted that, as shown in FIG. 3, within the casing of the switch 150 the plunger 149 is provided with an enlargement 149 forming an abutment for engagement with the casing to prevent separation of the plunger from the switch casing.

The switch 150 may be operatively connected (not shown) with any one of a number of apparatuses or devices such as an electrically powered pump, for example, to operate a hydraulic cylinder unit to effect a movement of a boom.

The pneumatic line which may control, for example, a movement of a boom is of the self-charging type due to the construction and arrangement of elements in the air transmitter 115. Due to the provision of the conically recessed valve 143 of the transmitter and the construction and arrangement of the valve seat which includes the gasket 12.7 of the transmitter, water is very effectively inhibited from dripping into the apertured upper end fitting 122 of the bellows 121. The normally open air line permits air to enter or leave it through the port 119 in the air transmitter, which port also serves to permit the escape of moisture from within the transmitter. The normally open air line permits air to escape as when the line is subjected to heat, and permits air to enter the line as when the line is subjected to cold temperatures.

While the air receiver is illustrated and described as having an operative connection with an electric switch, it will be understood that the bellows-equipped plunger of the air receiver may be employed to operate other devices such as valves, for example.

While only one form of the pneumatic control apparatus has been illustrated and described above, it will be apparent to those versed in the art that the control maytake other forms and is susceptible of many changes in details without departure from the principles of the invention and the scope of the claims.

What I claim is:

1. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having an orifice opening into the bellows; and valve means for closing the orifice and compressing the bellows through the end fitting to transmit air through the air line, the last-named means extending within the 'casing and being operable from without the latter, the

ceiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows Within the casing having: one end thereof connected to the air line, the other end of the bellows being free within the casing and provided. with a fitting having a central tubular part communicating: with and extending from the bellows and terminating in" a free end, the last-named end having a resilient member thereon to form a valve seat; and valve means for cooperation with said seat and movable to compress the bellows through the end fitting to transmit air through said line, the last-named means extending within the casing and being operable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being spring biased to a normal position; spaced from said fitting to permit ingress and egress off air from the bellows, and the casing having means providing for the admission and exhaust of air.

, 3. In a control mechanism of the pneumatic type, ant air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having a central tubular part communicating with and extending from the bellows and terminating in a free end, the last-named end having a generally conical peripheral surface; an O-ring seated in abutting relation to said surface and protruding therefrom to form a valve seat; and valve means for cooperation with said seat and movable to compress the bellows through the:

end fitting to transmit air through said line, the last-- named means extending within the casing and being op-- erable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being a manually depressible plunger spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the admission and exhaust of air.

4. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having a central part communicating with and extending from the bellows and terminating in a free end, the last-named end having a generally conical pe ripheral surface; an O-ring seated in abutting relation to said surface and protruding therefrom to form a valve seat; and valve means for cooperation with said seat and. movable to compress the bellows through the end fitting; to transmit air through said line, the last-named means extending within the casing and being operable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the admission and exhaust of air.

5. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having a central part communicating with and extending from the bellows and terminating in a free end, the last-named end having a generally conical pe-- ripheral surface; an O-ring seated in abutting relationto said surface and protruding therefrom to form a valve seat; and valve means for cooperation with said seat and movable to compress the bellows through the end fitting to transmit air through said line, the last-named means extendings within the casing and being operable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being a manually depressible plunger spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the admission and exhaust of air.

6. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having a central tubular part communicating with and extending from the bellows and terminating in a free end, the last-named end having a generally conical peripheral surface having a valve seat provided thereon; and valve means for cooperation with said seat and movable to compress the bellows through the end fitting to transmit air through said line, the last-named means extending within the casing and being operable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the admission and exhaust of air.

7. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having a central tubular part communicating with and extending from the bellows and terminating in a free end, the last-named end having a generally conical peripheral surface having a valve seat provided thereon, said valve seat being provided by a surface protruding from said conical peripheral surface; and valve means for cooperation with said seat and movable to compress the bellows through the end fitting to transmit air through said line, the last-named means extending within the casing and being operable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the ad mission and exhaust of air.

8. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free Within the casing and provided with a fitting having a central tubular part communicating with and extending from the bellows and terminating in a free end, the last-named end having a generally conical peripheral surface having a valve seat provided thereon, said valve seat being provided by a surface protruding from said conical peripheral surface; and valve means for cooperation with said seat and movable to compress the bellows through the end fitting to transmit air through said line, the last-named means extending within the casing and being operable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being a manually depressible plunger spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the admission and exhaust of air.

9. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having an orifice opening into the bellows; and valve means for closing the orifice and compressing the bellows through the end fitting to transmit air through the air line, the last-named means extending within the casing and being operable from without the latter, the valve means being spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the admission and exhaust of air.

10. In a control mechanism of the pneumatic type, an air transmitter connected to a remotely located air receiver by an air line, the transmitter comprising: a casing; a flexible resilient bellows within the casing having one end thereof connected to the air line, the other end of the bellows being free within the casing and provided with a fitting having a central tubular part communicating with and extending from the bellows and terminating in a free end, the last-named end having a generally conical peripheral surface; an O-ring seated in abutting relation to said surface and protruding therefrom to form a valve seat; and valve means for cooperation with said seat and movable to compress the bellows through the end fitting to transmit air through said line, the last-named means extending within the casing and being operable from without the latter, the valve means comprising a valve element having a conically recessed surface for cooperation with the valve seat, said valve element being spring biased to a normal position spaced from said fitting to permit ingress and egress of air from the bellows, and the casing having means providing for the admission and exhaust of air.

References Cited by the Examiner UNITED STATES PATENTS 330,221 11/1885 Garsed 6062.5 1,870,904 8/1932 Giesler 92-34 2,292,527 8/1942 Kraft 6062.6 2,358,032 9/ 1944 Rothwell et al. 92-34 2,562,847 7/1951 Spencer 6062.6 2,567,519 9/1951 Livingston 92-34 X 3,078,679 2/1963 Mortimer et al. 60-62.6

SAMUEL LEVINE, Primary Examiner.

ROBERT R. BUNEVICH, Examiner. 

1. IN A CONTROL MECHANISM OF THE PNEUMATIC TYPE, AN AIR TRANSMITTER CONNECTED TO A REMOTELY LOCATED AIR RECEIVER BY AN AIR LINE, THE TRANSMITTER COMPRISING: A CASING; A FLEXIBLE RESILIENT BELLOWS WITHIN THE CASING HAVING ONE END THEREOF CONNECTED TO THE AIR LINE, THE OTHER END OF THE BELLOWS BEING FREE WITHIN THE CASING AND PROVIDED WITH A FITTING HAVING AN ORIFICE OPENING INTO THE BELLOWS; AND VALVE MEANS FOR CLOSING THE ORIFICE AND COMPRESSING 